Fluid filter assemblies are used in a wide variety of applications ranging in scale from the industrial processing of liquids and gases to the residential purification of drinking water. In general, such fluid filtration devices are comprised of a filter element, a housing and a fluid seal. The purpose of the fluid seal is to ensure that fluid entering the housing is directed through the filter assembly in a predetermined path, viz., through the filter element.
Traditionally, fluid seals are discrete parts, such as skirted gaskets, which engage the outer surface of the filter element and the inner surface of the housing. These seals are usually secured to the filter element with an adhesive tape, an adhesive or an interference or compression fit; see, for example, U.S. Pat. No. 5,389,260. The process for applying these seals tends to be very labor intensive and suffers from the associated ergonomic, quality and training implications. With the skirted gasket, fluid pressure between the skirt and the filter element tends to force the seal away from the element, thus threatening the integrity of the seal. This is particularly troublesome if the seal is secured to the filter element by taping. Furthermore, the typically narrow width of a skirted gasket leaves the integrity of the seal susceptible to disruption by surface imperfections and particulate contamination. Yet another disadvantage of the taped-on seal is the tendency to fold back when inserted into the housing, once again threatening the integrity of the seal and the overall performance of the filter assembly. When the integrity of the fluid seal is compromised, the feed stream can bypass the filter element and weaken the performance of the element. With reverse osmosis elements, such leakage results in ion rejection rates and permeate flow rates being less than optimal.
It would be desirable to have a fluid filter assembly whose production more easily lends itself to automation, particularly with respect to the incorporation of the fluid seal. It would also be desirable to have a fluid filter assembly in which the integrity of the fluid seal was more reliable and less susceptible to damage or deformation during installation and operation.